As a result, the TSA “does not have a complete understanding” of breaches at the nation’s airports, says a report from the inspector general.

The report, published earlier this month, was requested by New Jersey Democratic Sen. Frank Lautenberg after a series of breaches at Newark Airport, including a knife bypassing TSA screening, passengers walking around security checkpoints and a dead dog transported without being screened for explosives.

TSA responded to those incidents with “corrective action,” according to the inspector general, but not all the problems received the same treatment.

The TSA took action to fix only 42% of the security breaches documented at Newark Airport, according to the report.

“There’s no consistency because there is no clear guidance on what to report and when to report,” Charles Edwards, acting inspector general at the Department of Homeland Security, told a congressional hearing on Wednesday. “One of our recommendations is that they have to have a comprehensive overight program where they provide clear guidance and how each of the airports need to be reporting and then TSA needs to follow through.”

Most of the incidents examined occurred in 2010, and the report says since then efforts to fix security breach vulnerabilities have improved.

Five other large U.S. terminals were visited by inspectors for comparison but the airports’ names were withheld from the public report.

Of the six airports visited, records were found detailing efforts to fix the causes of only 53% of the breaches.

Newark was the lowest-scoring. The highest-rated airport reported corrective action in 88% of the breaches.

“I’m going to tell you right now the next incident is going to come from the ground. It’s going to come from the shadow of the aircraft, it’s not going to come through the passenger terminal. I’m telling you that,” said Rep. John “Chip” Cravaack, R-Minnesota.

The inspector general also noted that while the agency did have “many programs and initiatives that report and track identified security breaches” they were “not all inclusive or centrally managed.”

This lack of comprehensive, centralized data was cited as preventing the use of information to “monitor trends or make general improvements to security.”

Problems with how incidents were categorized in reporting also were outlined in the report.

TSA workers at one airport reported “an improper bag handoff incident” in a database as a “sterile area access event” while another airport reported four similar incidents as “security breaches.”

Management at the agency concurred with the inspector general’s report.

“TSA acknowledges that it can further develop and expand its oversight programs for gathering and tracking airport security breaches,” wrote administrator John Pistole.

“TSA currently collects thousands of records of incidents and security breaches occurring at airports and other transportation facilities,” TSA spokesman David Castelveter told CNN in an e-mail. “TSA is coordinating appropriate revisions to relevant Operations Directives to develop a single definition of ‘Security Breach,’ addressing (the inspector general’s) recommendation.”